ABCD

Example

A
B
B
15
B
B
C
_
A
C
C
5
9
16
_
 
 
A
B
C
_
_
_

Solution

A
B
B
15
B
B
C
16
A
C
C
5
9
16
11
 
 
A
B
C
1
7
2
home
home

ABCD
ABCD

Number of exercises: